Oil Leaking after Oil Change...Seems Shady

Question

I went to Sears Auto Center. This was the third time I've gone there and every time I go they have to order a filter to be delivered. After the first time, I would tell them days in advance that they didn't have the filter last time and I had to wait. Each time I've gone it has been at least 1 hour and 15 minutes to get my vehicle back. Let's make matters worse!

The garage manager tells me they had to change the drain plug. He was just walking by and did not give a reason why. I saw the mechanic using a flashlight while he and another mechanic kept looking underneath my truck near the front. They were looking for about 5 minutes at it. They even lowered the hoist about halfway down from high up just to take a closer look.

He pulls the vehicle out. I ask him if anything was wrong because I saw him looking close with a flashlight. He said no everything is fine. I get home and find out (thankfully it was raining) that there was oil in the water behind my truck (pavement on slight decline). So I put some grocery bags underneath and sure enough over about 45 minutes a small puddle of oil shows up.

By the time I attempted to call back, they were closed.

1. I figure to take it back to them and tell them to fix it?
2. What do you think this could be? Did they put a lousy drain plug on to replace it or is it something more?
3. Should I even trust them to fix it when I know that mechanic knew it was leaking before giving me my truck back?
4. Doesn't this seem very sinister that he could give me the truck back knowing it was leaking?
5. I've already thought about calling the corporate office as this was beyond wrong; sound about right?

Answer 1

Without pictures, it's impossible to diagnose the location of your oil leak. Here's some possibilities:

1. The drain plug is not properly on. These don't need to be on tight to make a good seal, but they do need to be the proper size.
2. The oil filter isn't on properly. Again, this doesn't need to be on tight, but it does need to be seated properly.
3. Oil pan gasket. This is a fairly common leak point on many engines.
4. Leaking seal. On most vehicles, most of the oil circuit is internal to the engine. If the leak is coming from the engine itself (not the drain plug or oil filter or oil pan), it could be a seal that has rotten and cracked.

Since they thought to replace the drain plug, it suggests that they saw oil "outside the engine". What they were doing with the flashlight was probably trying to find where the leak was coming from. If your engine bay is dirty, and most engine bays are, it'll be near impossible to see where the leak is coming from without a good shampoo first.

From the options above, the drain plug is the cheapest and quickest to do. In my experience, I've had to replace drain plugs twice, but never because of leaks, always because the previous #@$&% used power tools to tighten the drain plug way too tight. They were probably guessing at the cause of the leak and working by elimination rather than shampooing the engine and running it (after the oil change) for 30-45 minutes to find the leak.